Time: 2025-07-11 11:20:55 Source: Codora.ai Author: java Reading: 453 times

theseblockchain worlds let's talk about thefirst one being the cibil attack thecibil attack is vector database aiwhen a user creates awhole bunch of pseudo Anonymous accountsto try to influence a network nowobviously on bitcoin and ethereum thisis really really difficult because auser needs to do all this work in proofof work or have a ton of collateral inproof of stake which again we'll talkabout in a bit the other more prevalentattack is what's known as a 51 percentattack now as we saw as part of ourconsensus protocol these blockchains aregoing to agree that the longest chain isthe one that they're going to go with solong as it matches up with 51% of therest of the network this means that ifyou have the longest chain and you havemore than 51% of the rest of the networkyou can do what's called a fork in thenetwork and bring the network onto yournow longest chain now cibil attacksobviously are when a single node or asingle entity tries to affect thedecentral of the network by tending tobe multiple different people althoughthey're just the same person or entityand like I said it's really difficult todo in proof of work and proof of stakeso you can see now that blockchains arevery Democratic whichever blockchain hasthe most Buy in and is the longest isthe blockchain that the whole system isgoing to corroborate when nodes producea new block and add it to the longestchain the other nodes will follow thislongest chain that the rest of thenetwork is agreeing with ADD thoseblocks to their chain and follow up sovery small reorganizations are actuallypretty common when a blockchain chainpicks a block from a different longestchain puts it on and then has to swap itout for another block and continue witha different blockchain however if agroup of nodes had enough nodes orenough power they could essentially be51% of the network and influence thenetwork in whatever direction that theywanted this is what's known as a 51%attack and it's happened on blockchainslike ethereum classic which is notethereum this is why the bigger ablockchain is the more decentralized andthe more secure it becomes so after youwatch this video you become a blockchainengineering expert I definitelyrecommend you run a note as well becauseyou are going to increase the securityof the network as a whole by running anode so proof of work is fantasticbecause it allows us to very easilyprotect against these Cil attacks andkeep our blockchains decentralized andsecure however it has some drawbacks aswell proof of work costs a lot ofelectricity because every single node isrunning as fast as they can to win thisrace to get the rewards this leads toobviously an environmental impact nowsince proof of work Nakamoto consensus alot of other protocols have taken thisidea and gone in a different directionwith a different civil resistanceprotocol a lot of them with theintention to be a lot moreenvironmentally friendly and the mostpopular one right now is proof of stakethere are some chains that are alreadyusing this proof of stake protocol andthat are live and thriving some of themare like Avalanche salana polygon polkadot and Tera and additionally ethereumis decided to upgrade to eth2 which willhave this proof of stake algorithm aswell well it'll also have some otherfeatures which we'll talk about in a bitnow as a quick aside all the tools thatwe're going to learn here are stillgoing to work in e two so depending onwhen you watch this everything here isstill valid so let's talk about proof ofstake now again this is a differentcivil resistance mechanism instead ofsolving this difficult problem proof ofstake nodes put up some collateral thatthey're going to behave honestly AKAthey stake in the example of ethereum 2nodes put up some ethereum as a stakethat they're going to behave honestly inthe network if they misbehave in thenetwork they are going to be slashed orremoved some of their state obviouslythis is a very good civil resistancemechanism because if you try to create awhole bunch of anonymous accounts theneach one of those accounts you have toput up some stake and if you misbehaveyou're going to run the risk of losingall the money that you put up ascollateral in this system miners areactually called validators becausethey're no longer binding anythingthey're actually just validating othernodes now unlike proof of work whichevery node is ing to be the first one tofind the Block in proof of stake nodesare actually randomly chosen to proposethe new block and then the rest of thevalidators will validate if that nodehas proposed the block honestly as wesaw with our cryptography lesson it'susually very easy for other nodes toverify if a proposal or a transaction ishonest now Randomness is a reallyimportant topic when we're talking aboutblockchains because keep in mind theseblockchains are deterministic systemsthey're walled Gardens from the rest ofthe world and as you you know adeterminate system by definition can'thave random numbers so how do we choosethe random validators in the system wellit changes from blockchain to blockchainand actually choosing the node willchange blockchain to blockchain but inE2 they're using what's called randow atleast for the original implementationthis is a decentralized autonomousorganization that collectively choosesthe random number and collectivelychooses which node is going to run nextwe aren't going to dive too deep intothis because there's a good chance thatthis might change in the future but wewill go into Randomness Solutions inblockchain later on in this course nowproof of stake obviously has some prosand cons as well Pros are that again itis a great civil resistance mechanismand a great way to figure out who theauthor of a block should be the otherPros are that it's way lesscomputationally expensive to figure outthe new block because instead of everysingle node on the network trying to dothis only one node needs to do this andthen the rest of the nodes just need tovalidate it the cons are that it'susually considered a slightly lessdecentralized Network due to the upfrontstaking costs it costs to participatenow this gets into a little bit of aphilosophical battle on howdecentralized is decentralized enoughand I think that's up to the communityto decide and as we

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